This might be the action reported.

JULY 21, 1864. (Sent 9.30 p.m.)
Brigadier-General RAWLINS,
Chief of Staff, City Point:
The following dispatch just received:
DEEP BOTTOM, July 21, 1864--8.45 p.m.
General WEITZEL,
Chief Engineer and Acting Chief of Staff:
Learning that the enemy were at work where they had the battery placed on the 16th instant, and knowing that if allowed to intrench themselves they could injure my camps and the pontoon bridge, and obstruct navigation, I ordered the Eleventh Maine, under Lieutenant-Colonel Hill, to the bluff below Four-Mile Creek, with instructions to advance and occupy the enemy's position, which was done without loss, the enemy's picket falling back as our line advanced. Colonel Hill now holds the ground formerly occupied by the enemy, which is about one mile and a quarter in front of our work on the bluff and not far from Sweeney's Pottery. He has leveled the battery. Colonel Hill reports quite a force in his front. One lieutenant and 10 enlisted men were captured and have been sent to corps headquarters.
R. S. FOSTER,
Brigadier-General.

Will the commanding general please order' General Benham to send me another bridge 600 feet long, so that I can throw it from Jones' Neck to the down-river bank of Four Mile Creek, and thus enable us to re-enforce that bank if necessary, and thus keep the enemy from erecting batteries on that bank as this attempt was to command and shell our troops which are in position on the up-river bank of that creek.
G. WEITZEL,
Brigadier-General and Acting Chief of Staff.
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OR1 V40 Pt. 3 p. 377